Dual tooth crown



F. o. JAQUES, JR

DUAL TOOTH CROWN Filed May 10. 1928 Patented Nov. 5, 1929 DUAL 'roorri onown Application filed May 10,

My invention has reference to an improvement in the art of dentistry and more particularly to an improvement in dual tooth crowns, whereby the dual tooth crown is ma- 5 terially improved and strengthened.

Manufacturers of tooth crowns have tried for a long time to make a tooth crown entirely of porcelain and they have failed to make one that will do the work required of a porcelain crown. Such porcelain tooth crowns must have the shape of the tooth to be crowned, therefore, they must taper to a knife edge at the open end of the crown or where the crown meets the gum line. This makes this part of the porcelain crown so thin and weak that when in use on a tooth, it will break and crumble away from the tooth, thereby ruining the utility of the crown.

The object of my invention is to, improve the construction of a porcelain tooth crown and I accomplish this object by constructing a dual tooth crown, said dual tooth crown consisting of an inner crown or shell of metal and an outer crown or shell formed entirely of porcelain, the shape of the tooth to be crowned, the dual parts of the crown being cemented together by a low fusible porcelain.

A further object of my invention is to strengthen the crown with an overhanging annular lip which laps over onto the thin open end portion of the porcelain crown, thereby eliminating breaking or crumbling away of the porcelain, when in use.

Another object of my invention is to provide such a dual tooth crown with an annular strengthening member which extends around the crown and materially strengthens the crown.

My invention consists in the peculiar and novel construction of a dual tooth crown, said dual tooth crown consisting of an inner metal crown shell and an outer porcelain crown shell, means for reinforcing the porcelain shell and details of construction, as will be more fully set forth hereinafter and claimed.

Figure 1 is a perspective labial view of the. inner metal crown shell of my improved dual tooth crown and showing the same partly in section. V

1928. Serial No. 276,651. 1

Figure is a sectional vlew through the dual tooth crown and showing the same as a porcelain crown on a natural human tooth.

All of the figures are greatly enlarged to more clearly show my invention.

In the drawing A indicates a dual tooth crown consisting of an outer crown shell B, of porcelain and an inner crown shell C, of

.metal, such as platinum, and D, a natural tooth.

The outer crown shell B, of porcelain has the usual closed end, open end 5, labial portion 6, lingual portion 7, and the shape and size of the tooth to be crowned. The porcelain crown shell tapers to a knife edge portion 8, at the open end 5, as shown in FigureQ, and its inner portion 9 is shaped to fit the inner metal crown shell C.

The inner metal crown shell C, has the usual closed end and corresponding open end 5 labial portion 6 lingual portion 7 and the shape and size of the tooth to be crowned.

Extending around the outer surface and forming a part of the inner metal crown shell 1 C, is an overlapping porcelain reinforcing undercut lip 10, shaped to conform to the nat- 8 ural curve of the gum line. This-lip 10, is

placed a predetermined distance from the open end 5 of the metal crown shell C. t When in use the natural tooth D, is shaped i c as shown 1n Figure 4, to be inserted into the inner metal crown shell C, of the dual tooth crown A. The thin portion of the inner crown shell from the annular reinforcing lip 10 to the open end 5 of the inner crown shell C, is cut away and shaped to fit the gum 9 line. The porcelain crown A, is then placed over the tooth to be crowned andcemented to the tooth.

It is evident that my improved dual porcelain tooth crown could be modified to meet various kinds or shapes of teeth, without departing from my invention, which is, a dual porcelain tooth crown consisting of an outer shell of porcelain, an inner shell of metal and an overlapping reinforcing lip extending over the outer porcelain shell.

Having thus described my invention I claim as new V A dual tooth" crown comprising an outer crown shell of porcelain, which tapers to a thin edge at the open end of the shell and an inner crown shell of metal cemented together, said inner metal crown shell having-an outer annular undercut overlapping lip shaped to conform to the gum line and overlapping the thin edge portion of the porcelain outer crown shell and a thin cylindrical portion which extends from the annular undercut overlapping lip to the open end of the inner crown shell, said thin cylindrical portion extending under the natural gum beyond the gum line.

In testimony whereof I have signed my name to this specification.

FERNANDO OSCAR JAQUES, JR. 

